The present invention relates to a method for regulating the load in a thermal engine having a power generator, in order to keep the voltage or the frequency at the terminals of the power generator constant during load changes by a constantly even power usage.
In the case of thermal engines, e.g., a Stirling engine having a linear generator, concepts are applied for regulating load which either require expensive mechanics or use an external electric load in order to keep the voltage (and also the frequency, in the case of rotary machines) at the terminals constant, as U.S. Pat. No. 5,385,021 and U.S. Pat. No. 5,502,968 show.
The necessary mechanics are not only cost-intensive, but also susceptible to malfunctions. The external electric load converts high-value electric current into low-value heat and is consequently uneconomical.
It is an object of the present invention to provide a method which can be achieved without expensive mechanics that are susceptible to malfunctions and in which surplus electrical energy can simply be conducted to the thermal energy process.
This object is achieved according to the present invention in that an electronic system determines the difference between the maximum power capacity and the attached electrical load, and this difference can in turn be conducted by a variable load resistor to the thermal energy process as high-temperature heat.
The electrical energy that is not consumed by a load is retained in the thermal energy process.
The difference between the maximum power capacity of the thermal engine and the present load can be determined quickly and reliably by an electronic system having a high degree of operating reliability. This power difference may then in turn be conducted to the thermal energy process via an assigned variable load resistor at a high temperature.
This can occur in different manners. One embodiment of the present invention is thus characterized in that, in a thermal engine having a Stirling engine and a heater head, the variable load resistor directly heats the heater head as a heater resistor.
Another possibility is provided in that the variable load resistor heats the fuel-air mixture supplied to the thermal engine as a heater resistor.
According to another embodiment, the fuel supply to the thermal engine is reducible in order to prevent a temperature increase in the heater head.